I am trying to swap between two panels by using the slide effect. As one panel slides into view (hidden->visible), the older panel slides away (visible->hidden) in the appropriate stacking order.

The problem I am having is I cannot initialize the position of the panels on start-up. If I click through all the menu items, the slide effect positions the panels in their properly position and everything looks to behave as expected. I have tried to position the panels using the onLoad event without success.